The invention relates at least to a method for measuring and displaying, in particular simultaneously measuring and displaying, different particle concentrations, in particular particulate matter concentrations, preferably in a flow, using a photometric scattered light unit consisting of a light transmitter which emits light signals, preferably pulsed light signals, into a measurement volume and a light-sensitive receiver system, which is arranged at an angle and which receives the scattered light of the particles which form the particle concentration, wherein the advantageously present through-flow of the fluid to be examined is carried out with a usually right-angled alignment in relation to the light transmission unit and light reception unit.
The invention furthermore relates to apparatuses for simultaneously measuring and displaying different particulate matter concentrations.
Very high particulate matter concentrations are generated in urban and industrial regions as a result of combustion processes. Sometimes, the values are so high (>100 to 200 μg/m3) that a permanent stay in such regions is harmful to health. The cities of Beijing and Shanghai have already been classified as no longer inhabitable regions by the WHO. If attempts are made to accurately measure various particulate matter concentrations, e.g. with a resolution of 1 to 2 μg/m3, it becomes clear that this is linked to very high outlay and costs (3000 to 30,000). Photometric and gravimetric systems have prevailed. The measurement principles of a scattered light photometer or gravimetric measuring system are already part of the prior art. There are numerous companies, such as Apollo, Honeywell, Sharp, Shinjei et al., which offer OEM sensors on the basis of the scattered light method at relatively low costs (10 to 20). The accuracy of these OEM sensors lies at approximately 25 to 100 μg/m3. Using this, it is possible to control indoor air purifiers, which start with purification at concentrations of 50 to 100 g/m3 and switch off again at approximately 20 μg/m3. Well-known brands have already equipped indoor air purifiers with such sensors. However, a more accurate, permanently reliable determination of the particulate matter concentration is currently not possible therewith. However, since there is great need for a cost-effective determination of the particulate matter concentrations and in order to protect the health of living beings, a novel cost-effective method for detecting the so-called “particulate matter”, abbreviated PM, was developed. Determining PM1.0, PM2.5 and PM10 with mean particle sizes of 1.0 μm, 2.5 μm and 10 μm is conventional. This method not only allows the determination of a fraction such as e.g. the important PM2.5, but also allows the simultaneous determination of a plurality of fractions, such as e.g. PM1.0, PM2.5 and PM10. The resolution threshold of particles lies at approximately 0.3 μm. Using this, even accurate determination of PM0.5 is possible in a safe and reliable manner. An accuracy of a few μg/m3 in the measurement range up to 100 μg/m3 may be obtained therewith.